The background art enables a harmonic balance of the sound spectrum of the fundamental and overtones of a drum to be achieved only when a closed shell or sound box is present (timpani, orchestral kettledrum, Indian tabla).
The invention is therefore based—as noted above—on the object of achieving a balanced sound spectrum in a drum.
This object is achieved by the resonance device specified in claim 1, which is characterized in that ring resonators in closed and/or open design are present on a drum kettle or shell that is covered by at least one membrane, beneath the membrane.
The dependent claims set out preferred embodiments of the invention, according to which the drum kettle or the shell is provided at each end with a membrane, a ring resonator being provided beneath the membrane.
According to a further preferred embodiment, the resonance device has ring resonators in the form of a continuous groove beneath a membrane on a drum kettle or shell.
In such a resonance device in closed design the cavity of the ring resonator may be spanned by a membrane.
Owing to the resonance device shown, harmonic vibration characteristics of a membrane (2) are ensured even in a sound box or drum shell (1) that is open on one side. The ring resonator in closed design (3) defines the overtone characteristics of the drum shell in a way so that only desired, harmonic frequencies are created. The ring resonator in open design (4) defines the overtone characteristics of the membrane in a way so that only desired, harmonic frequencies are created. In this way the energy conversion efficiency of the drum is increased and the drumming technique used to achieve certain predominant, desired, dominant tones of the drum sound is facilitated. The sound volume at the same stroke intensity is higher and makes it easier for the musician to fit in with the dynamics of an orchestra or ensemble.
The resonance device comprises one to two or more ring resonators (3,4) which are positioned on the edge of a kettle or shell (1) of a drum, beneath the membrane (2). The ring resonators (3, 4) may be open (4) via a gap (5) or closed (3). The ring resonators (3,4) may each be used individually or in combination.
Both ring resonators (3,4) may be shaped to have a triangular or a round profile. The closed ring resonator (3) has a precisely dimensioned volume that is covered by the membrane (2) and effects desired, harmonic resonance overtone characteristics of the drum shell (1).
The ring resonator (4) that is open via a gap (5) likewise has a precisely dimensioned volume and effects desired, harmonic resonance overtone characteristics of the membrane (2) that spans the ring resonator (4).